Absolutely essential. Fumes from lead-free solder fluxes are nasty [1]. I find that bench-top "fume extractors", consisting of a fan and thin dust filter, are extremely noisy and essentially useless. I love my Hakko FA430-16. It's relatively quiet such that a regular conversation can be had in its presence, and it really works with the right hose & hood setup.
I wouldn't call the simple fans useless - just the fact that the fumes are being blown away from your face is a huge improvement over not even having that.
Of course there needs to be somewhere for them to go, but if you can have an open window close to your bench, that solves that problem quite nicely.
As someone who owns a FA430 and has a sensitivity to flux fumes causing headaches and drowsiness, I agree with everything in this comment. Keep in mind you can become sensitized to flux fumes after repeated exposure (happened to me) so IMO it's better to go overkill on fume extraction before it becomes a problem.
1: https://www.hse.gov.uk/lung-disease/electronics-soldering.ht...